Design and validation of the ADNI MR protocol

Area of Science:

• Neuroimaging
• Alzheimer's Disease Research
• Biomarker Discovery

Background:

• Longitudinal consistency in Alzheimer's Disease Neuroimaging Initiative (ADNI) magnetic resonance imaging (MRI) data is crucial for tracking disease progression over two decades.
• Advancements in MRI technology necessitate protocol updates to maintain data integrity and incorporate novel imaging techniques.

Purpose of the Study:

• To describe and justify the updated MRI protocols for phase four of the Alzheimer's Disease Neuroimaging Initiative (ADNI4).
• To introduce new MRI sequences and technologies aimed at enhancing data acquisition and biomarker extraction.
• To provide a robust database for testing advanced imaging strategies in Alzheimer's disease diagnosis and monitoring.

Main Methods:

• Implementation of nine MRI sequences in the ADNI4 protocol, including updates for hardware and software compatibility.
• Introduction of key sequence additions/changes: compressed sensing (CS) T1-weighting, pseudo-continuous arterial spin labeling (ASL) across vendors, multiple-post-labeling-delay ASL, 1 mm³ isotropic 3D fluid-attenuated inversion recovery, and CS 3D T2-weighted imaging.
• Continuous rollout of sequences as site-specific upgrades become available.

Main Results:

• The ADNI4 protocol incorporates advanced techniques like compressed sensing and multi-band imaging to potentially reduce scan times.
• New sequences are designed to yield valuable imaging biomarkers for Alzheimer's disease.
• Protocols are being streamlined for safety screening and therapy monitoring.

Conclusions:

• The ADNI4 MRI protocols are designed to maintain longitudinal data consistency while integrating cutting-edge neuroimaging technologies.
• These updated protocols will facilitate the extraction of critical imaging biomarkers.
• The ADNI4 database will serve as an essential resource for the neuroimaging community to validate advanced imaging strategies and improve diagnostic accuracy across the Alzheimer's disease spectrum.